scholarly journals Biogeographic evidence supports the Old Amazon hypothesis for the formation of the Amazon fluvial system

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12533
Author(s):  
Karen Méndez-Camacho ◽  
Omar Leon-Alvarado ◽  
Daniel R. Miranda-Esquivel

The Amazon has high biodiversity, which has been attributed to different geological events such as the formation of rivers. The Old and Young Amazon hypotheses have been proposed regarding the date of the formation of the Amazon basin. Different studies of historical biogeography support the Young Amazon model, however, most studies use secondary calibrations or are performed at the population level, preventing evaluation of a possible older formation of the Amazon basin. Here, we evaluated the fit of molecular phylogenetic and biogeographic data to previous models regarding the age of formation of the Amazon fluvial system. We reconstructed time-calibrated molecular phylogenies through Bayesian inference for six taxa belonging to Amphibia, Aves, Insecta and Mammalia, using both, nuclear and mitochondrial DNA sequence data and fossils as calibration points, and explored priors for both data sources. We detected the most plausible vicariant barriers for each phylogeny and performed an ancestral reconstruction analysis using areas bounded by major Amazonian rivers, and therefore, evaluated the effect of different dispersal rates over time based on geological and biogeographical information. The majority of the genes analyzed fit a relaxed clock model. The log normal distribution fits better and leads to more precise age estimations than the exponential distribution. The data suggested that the first dispersals to the Amazon basin occurred to Western Amazonia from 16.2–10.4 Ma, and the taxa covered most of the areas of the Amazon basin between 12.2–6.2 Ma. Additionally, regardless of the method, we obtained evidence for two rivers: Tocantins and Madeira, acting as vicariant barriers. Given the molecular and biogeographical analyses, we found that some taxa were fitted to the “Old Amazon” model.

2014 ◽  
Vol 62 (3) ◽  
pp. 235 ◽  
Author(s):  
S. Safaei Chaei Kar ◽  
F. Ghanavati ◽  
M. R. Naghavi ◽  
H. Amirabadi-zade ◽  
R. Rabiee

Onobrychis, comprising more than 130 species, is a genus of the family Fabaceae. At this time, the interspecies relationship of this biologically important genus is still a subject of great discussion and debate. To help resolve this disagreement, we used molecular phylogeny to analyse internal transcribed spacer (ITS) and trnL–trnF sequences of 76 species of Onobrychis. Bayesian interference, maximum parsimony and maximum likelihood analyses of nuclear ITS and plastid trnL–trnF DNA sequence data generated trees with strong posterior probability for two groups: Onobrychis subgen. Sisyrosema (including: Heliobrychis, Hymenobrychis, Afghanicae and Anthyllium sections) along with Laxiflorae section in Group I and Onobrychis subgen. Onobrychis (except Laxiflorae section) in the other (Group II). The Laxiflorae section roots back to the ancestral node for Sisyrosema subgen. O. viciifolia (cultivated species), which is closely associated with O. cyri var. cyri, suggesting that the latter may be a wild progenitor of O. viciifolia. The present study supported the paraphyly of subgenera Onobrychis and Sisyrosema. The study proposed the paraphyletic nature of the sections Onobrychis, Dendrobrychis, Heliobrychis and Hymenobrychis. Together with our molecular phylogenetic analyses we present a review of Onobrychis morphology and discuss and compare our results with those of earlier morphological and molecular phylogenetic analyses.


Phytotaxa ◽  
2018 ◽  
Vol 350 (1) ◽  
pp. 42 ◽  
Author(s):  
GALINA V. DEGTJAREVA ◽  
MICHAEL G. PIMENOV ◽  
TAHIR H. SAMIGULLIN

The systematic position of three Apiaceae-Apioideae taxa, Pinacantha porandica, Ladyginia bucharica and Peucedanum mogoltavicum, from Middle Asia and Afghanistan, is clarified based on nrITS DNA sequence data. In the molecular phylogenetic tree, the monotypic Pinacantha is placed in unresolved position within the Ferulinae. Although there is no morphological information on essential characters, we propose a new position of Pinacantha porandica within the genus Ferula. As a result a new combination Ferula porandica is proposed, with a new section Pinacantha to accommodate it. The attribution of Peucedanum mogoltavicum to Ferula has been confirmed, its correct name being Ferula lithophila. The genus Ladyginia should not be included in Ferula, its closest relatives being Mozaffariania and Glaucosciadium from the Glaucosciadium Clade.


2020 ◽  
Vol 190 (3) ◽  
pp. 1002-1019 ◽  
Author(s):  
Donald L J Quicke ◽  
Sergey A Belokobylskij ◽  
Yves Braet ◽  
Cornelis van Achterberg ◽  
Paul D N Hebert ◽  
...  

Abstract A new tribe of braconid wasps provisionally included in the Rhyssalinae, Laibaleini trib. nov., type genus Laibalea gen. nov. (type species Laibalea enigmatica sp. nov.), from Kenya and the Central African Republic, is described. A molecular dataset, with emphasis on basally derived taxa based on four gene fragments (28S D2–D3 expansion region, COI barcode, elongation factor 1-alpha and 16S ribosomal DNA), was analysed both alone and in combination with a morphological dataset. Molecular phylogenetic placement of the new species into an existing subfamily is complicated by the extreme sequence divergence of the three sequences obtained for Laibalea. In both the combined sequence analysis and the combined DNA plus morphological tree, Laibalea is recovered as a sister group to the Rhyssalinae plus all non-cyclostome lineage braconids excluding Mesostoinae, Maxfischeriinae and Aphidiinae. A consensus of morphological characters and molecular analyses suggests inclusion of Laibalea either in the otherwise principally Holarctic subfamily Rhyssalinae or perhap more basally, in the principally Gondwanan Mesostoinae s.l., although we cannot exclude the possibility that it might represent a separate basal lineage. We place Laibalea in its own tribe, provisionally included in Rhyssalinae. The DNA sequence data are presented for several genera for the first time. Avga, the type genus of Avgini, is shown not to belong to Mesostoinae s.l. or Hormiinae, but its exact relationships remain uncertain. The generic compositions of Rhyssalinae and Mesostoinae s.l. are revised. Anachyra, Apoavga, Neptihormius, Neoavga and Opiopterus are shown to belong to Mesostoinae s.s. A key to the tribes of Rhyssalinae is provided.


2004 ◽  
Vol 85 (1) ◽  
pp. 45-48 ◽  
Author(s):  
Linda M. Kohn

Astract Phylogenetic or genealogical interpretation of DNA sequence data from multiple genomic regions has become the gold standard for species delimitation and population genetics. Precise species concepts can inform quarantine decisions but are likely to reflect evolutionary events too far in the past to impact disease management. On the other hand, multilocus approaches at the population level can identify patterns of endemism or migration directly associated with episodes of disease, including host shifts and associated changes in determinants of pathogenicity and avirulence. We used the genome database of Magnaporthe grisea to frame a comparative, multilocus genomics approach from which we demonstrate a single origin for rice infecting genotypes with concomitant loss of sex in pandemic clonal lineages, and patterns of gain and loss of avirulence genes. In the Sclerotinia sclerotiorum pathosystem, we identified significant associations of multilocus haplotypes with specific pathogen populations in North America. Following the introduction of a new crop, endemic pathogen genotypes and newly evolved migrant genotypes caused novel, early-season symptoms.


2004 ◽  
Vol 17 (2) ◽  
pp. 145 ◽  
Author(s):  
Randall L. Small ◽  
Richard C. Cronn ◽  
Jonathan F. Wendel

Molecular data have had a profound impact on the field of plant systematics, and the application of DNA-sequence data to phylogenetic problems is now routine. The majority of data used in plant molecular phylogenetic studies derives from chloroplast DNA and nuclear rDNA, while the use of low-copy nuclear genes has not been widely adopted. This is due, at least in part, to the greater difficulty of isolating and characterising low-copy nuclear genes relative to chloroplast and rDNA sequences that are readily amplified with universal primers. The higher level of sequence variation characteristic of low-copy nuclear genes, however, often compensates for the experimental effort required to obtain them. In this review, we briefly discuss the strengths and limitations of chloroplast and rDNA sequences, and then focus our attention on the use of low-copy nuclear sequences. Advantages of low-copy nuclear sequences include a higher rate of evolution than for organellar sequences, the potential to accumulate datasets from multiple unlinked loci, and bi-parental inheritance. Challenges intrinsic to the use of low-copy nuclear sequences include distinguishing orthologous loci from divergent paralogous loci in the same gene family, being mindful of the complications arising from concerted evolution or recombination among paralogous sequences, and the presence of intraspecific, intrapopulational and intraindividual polymorphism. Finally, we provide a detailed protocol for the isolation, characterisation and use of low-copy nuclear sequences for phylogenetic studies.


2011 ◽  
Vol 23 (3) ◽  
pp. 211-224 ◽  
Author(s):  
G.C. Grobler ◽  
A.D.S. Bastos ◽  
A.M. Treasure ◽  
S.L. Chown

AbstractThe biogeography of the South Indian Ocean Province (SIP) biotas has long been controversial. Much of the discussion has been based on interpretation of species distributions, based on morphological or anatomical delimitations. However, molecular phylogenetic approaches elsewhere have recently shown that interpretations based solely on morphological data may be misleading. Nonetheless, few studies have employed molecular phylogenetic approaches to understand the biogeography of the SIP biotas. We do so here for theEctemnorhinusgroup of genera, a monophyletic unit of weevils endemic to the region. We use mitochondrial cytochrome oxidase I DNA sequence data to reconstruct relationships among 13 species and 22 populations in the generaPalirhoeus,BothrometopusandEctemnorhinus. On the basis of this analysis we find little support for separating the genusPalirhoeusfromBothrometopus, and little support for the morphologically-based species groups currently recognized withinBothrometopus. Using a molecular clock we show that dispersal among islands probably took place against the prevailing wind direction. These data also support a previous hypothesis of radiation of the epilithic generaBothrometopusandPalirhoeusduring the Pliocene/early Pleistocene, but reject the hypothesis that the genusEctemnorhinusradiated following the last glacial maximum. We show thatBothrometopus parvulus(C.O. Waterhouse) on the Prince Edward Islands comprises two species that are not sister taxa. We name the second speciesBothrometopus huntleyin. sp. and provide a description thereof.


Phytotaxa ◽  
2017 ◽  
Vol 323 (1) ◽  
pp. 27 ◽  
Author(s):  
VLADIMIR E. FEDOSOV ◽  
ALINA V. FEDOROVA ◽  
ELENA A. IGNATOVA ◽  
MICHAEL S. IGNATOV

The genus Seligeria is revised based on morphological and DNA sequence data of nuclear ITS and chloroplastic trnL-F. Fifteen species from most infrageneric units of the genus are recovered in two well supported phylogenetic clusters that are also distinctive in morphology. The clade with the type species of the genus, S. pusilla, includes also S. donniana, S. brevifolia, S. calcarea, S. patula, S. tristichoides, S. trifaria, and S. oelandica. These species are characterized by short, cupulate or turbinate capsules widened towards the mouth, and the lack of a stem central strand. Another clade includes species with rather long, mainly ovate to cylindrical capsules and more or less developed stem central strand: S. campylopoda, S. recurvata, S. subimmersa, S. diversifolia, and S. polaris. These two clusters do not show sister relationships, but the second one appears more closely related to the Blindia clade. To resolve the apparent paraphyly, the latter phylogenetic group is segregated in a genus Blindiadelphus. In some aspects of morphology and ecology it is intermediate between Seligeria s. str. and Blindia, but differs from both genera in subquadrate upper leaf cells and thin- to moderately thick-walled rectangular exothecial cells. Molecular phylogenetic analyses revealed heterogeneity within the specimens previously referred to Blindiadelphus campylopodus, indicating a presence in Asian Russia of an undescribed species that is described here as Blindiadelphus sibiricus. It differs from B. campylopodus by the larger spores and typically rounded leaf apices. The isotype specimen of S. galinae appeared to be nearly identical to S. donniana in the sequences of ITS and trnL-F, and examination of morphology revealed no substantial differences between these species. Thus, we consider S. galinae as a synonym of S. donniana. The genus Blindiadelphus includes species of Seligeria subg. Blindiadelphus and S. subg. Cyrtoseligeria, which however are found intermingled in the molecular phylogenetic analysis. Thus the genus Blindiadelphus is accepted without any infrageneric taxa. The phylogenetic tree is congruent with the subdivision of the genus Seligeria s.str into subg. Seligeria, subg. Anodon, subg. Megalosporia and one newly established subgenus Robustidontia for S. brevifolia.


2019 ◽  
Vol 42 (1) ◽  
pp. 228-260 ◽  
Author(s):  
H. Voglmayr ◽  
M.B. Aguirre-Hudson ◽  
H.G. Wagner ◽  
S. Tello ◽  
W.M. Jaklitsch

Based on DNA sequence data, the genus Leptosillia is shown to belong to the Xylariales. Molecular phylogenetic analyses of ITS-LSU rDNA sequence data and of a combined matrix of SSU-ITS-LSU rDNA, rpb1, rpb2, tef1 and tub2 reveal that the genera Cresporhaphis and Liberomyces are congeneric with Leptosillia. Coelosphaeria fusariospora, Leptorhaphis acerina, Leptorhaphis quercus f. macrospora, Leptorhaphis pinicola, Leptorhaphis wienkampii, Liberomyces pistaciae, Sphaeria muelleri and Zignoëlla slaptonensis are combined in Leptosillia, and all of these taxa except for C. fusariospora, L. pinicola and L. pistaciae are epitypified. Coelosphaeria fusariospora and Cresporhaphis rhoina are lectotypified. Liberomyces macrosporus and L. saliciphilus, which were isolated as phloem and sapwood endophytes, are shown to be synonyms of Leptosillia macrospora and L. wienkampii, respectively. All species formerly placed in Cresporhaphis that are now transferred to Leptosillia are revealed to be non-lichenized. Based on morphology and ecology, Cresporhaphis chibaensis is synonymised with Rhaphidicyrtis trichosporella, and C. rhoina is considered to be unrelated to the genus Leptosillia, but its generic affinities cannot be resolved in lack of DNA sequence data. Phylogenetic analyses place Leptosillia as sister taxon to Delonicicolaceae, and based on morphological and ecological differences, the new family Leptosilliaceae is established. Furfurella, a new genus with the three new species, F. luteostiolata, F. nigrescens and F. stromatica, growing on dead branches of mediterranean fabaceous shrubs from tribe Genisteae, is revealed to be the closest relative of Delonicicola in the family Delonicicolaceae, which is emended. ITS rDNA sequence data retrieved from GenBank demonstrate that the Leptosilliaceae were frequently isolated or sequenced as endophytes from temperate to tropical regions, and show that the genus Leptosillia represents a widely distributed component of endophyte communities of woody plants.


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